关键词: 低压涡轮, 性能试验, 效率, 封严气, 雷诺数, 叶尖间隙

Abstract: Turbine rig test is the most important way to evaluate the turbine performance in which the accuracy of efficiency measurement is very important to the test results, but it will be affected by many process factors. Based on the results of low-pressure turbine (LPT) rig test, this paper analyzes the effects of inlet and outlet flow field, sealing flow temper-ature/mass flow rate, Reynolds number, tip clearance, mechanical loss and efficiency definition to turbine test efficien-cy, which provides reference for turbine performance test scheme design, instrumentation design and test data analy-sis. By setting the sealing flow with the same temperature as main flow and covering thermal insulation material at inlet outer casing during test, the radial deviation of the inlet total temperature is less than 2K and the circumferential deviation is less than 1 K. According to the measurement results of turbine outlet movement, the circumferential distri-bution of probes may bring 0.14% test efficiency deviation. When the temperature ratio of seal gas to main flow in-creases by 0.1, the efficiency decreases by 0.11%, the flow rate increases by 1%, and the efficiency decreases by 0.29%. LPT efficiency decreases as Reynolds number falls, the reduction in efficiency from take off to cruise is above 1%. t different state points of turbine characteristics, the efficiency deviation caused by different radial clearances reaches 0.66%, so the clearance influence should be corrected in data analysis. In addition, the definition of mechani-cal loss and efficiency can affect the test efficiency by more than 0.3%.

Key words: low pressure turbine, rig test, efficiency, sealing flow, Reynolds number, tip clearance